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DirecTV-10
DirecTV-10 is a Boeing model 702 direct broadcast satellite that provides high definition television (HDTV) to DirecTV subscribers in North America.〔(Boeing Directv-10 specifications )〕 It was launched by International Launch Services on July 7, 2007 from the Baikonur Cosmodrome in Kazakhstan aboard an Enhanced Proton Breeze-M rocket.〔(Spaceflight Now | Tracking Station | Worldwide launch schedule )〕 After about two months of in-orbit testing, the satellite was moved to its operating position at 103.0° west longitude.〔http://www.lyngsat.com/Spaceway-1-and-DirecTV-10-12.html Spaceway 1 & DirecTV 10/12 at 102.8°W LyngSat〕 This was the third DirecTV satellite launched on a Proton rocket. Prior launches include DirecTV-8, which was launched on May 22, 2005, and DirecTV-5, which was launched on May 7, 2002.
DirecTV contracted with Boeing in 2004 to build three identical 702 model satellites — DirecTV-10, 11 and 12. DirecTV-11 was launched on March 19, 2008 and DirecTV-12 was launched on December 29, 2009. The satellites were purchased to significantly increase the number of national and local HDTV channels DirecTV offers.〔(Gunter's Space Page - Information on Launch vehicles, Satellites, Space Shuttle and Astronautics )〕
== Technology ==
DirecTV-10 transmits MPEG-4 encoded signals, a compression standard which is more efficient than MPEG-2 which DirecTV uses for standard definition and a small number of HD channels. The use of MPEG-4 compression allows the satellite to carry significantly more channels than it could using MPEG-2 compression. Receiving signals from DirecTV-10 requires an advanced receiver capable of decoding MPEG-4 signals, such as the H21 or HR21, and a 5-LNB Ku/Ka dish, such as the AT-9 "Sidecar". These receivers also receive MPEG-2 channels and offer interactive services.
DirecTV-10 and DirecTV-11 are co-located with the SPACEWAY-1 and SPACEWAY-2 satellites, respectively. The SPACEWAY satellites were originally designed so that 500 MHz of spectrum would be used for simple one-way broadcasting and 500 MHz for a broadband 2-way internet service. At the request of DirecTV, Boeing disabled the on-board processing payload designed to deliver enhanced connectivity for the 2-way internet service. DirecTV-10 and DirecTV-11 use this 500 MHz of spectrum for yet more simple one-way broadcast HDTV.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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